An analog-to-digital converter (ADC) converts an analog signal (e.g., voltage level) into a corresponding digital signal (binary word). There are numerous ways to implement an ADC. A conventional type of ADC is an incremental converter. An incremental converter utilizes an integrator and comparator and a pair of references. The input is integrated on one phase of the clock cycle. The reference is then integrated in the opposite direction in the second phase of the clock cycle. The reference selection, positive or negative, is driven by the comparator, always integrating back to zero. The number of cycles in which the comparator output is positive is counted to obtain the digital result. The incremental ADC makes 2n comparisons to form an n-bit conversion.
Yet another conventional type of ADC is a delta sigma ADC. The delta sigma ADC utilizes the same integrator/comparator topology. Rather than integrating the comparator output in a counter, the comparator result is processed in a decimator.
Such conventional ADCs utilize a fixed architecture. That is, a conventional ADC is not reconfigurable after fabrication. For example, conventional ADCs include fixed architecture integrators, fixed architecture amplifiers, or fixed architecture comparators, and are not reconfigurable to implement all three functions: integrator, amplifier, and comparator. That is, the same circuit element cannot be reused to implement the above listed three different functions. Such conventional ADCs suffer from pre-selected tradeoffs made during fabrication. In addition, conventional ADCs utilize single ended switched capacitor circuits.